Particle pump methods and devices

Abstract

Methods and devices are provided for transfer of particulate material, such as biomass feedstocks, into and out of pressurized reactors. Improved sluice devices have an L-shaped sluice chamber having an upper, vertical component in communication with a horizontal loading chamber and a lower component in communication with a vertical reactor inlet or outlet. Piston valves seal the sluice inlet and outlet by axial displacement across the vertical component of the sluice chamber and across the vertical reactor inlet or outlet. Relative to other methods for reactor unloading, these devices consume less steam and significantly reduce furfural content of unloaded, pretreated biomass. An optional hybrid plug/sluice method of biomass feeding using the devices permits biomass loading at sluice pressures intermediate between atmospheric and reactor pressure, thereby reducing “pump cycle” time and increasing biomass throughput capacity.

The invention claimed is: 
     
       1. An apparatus for removing pretreated biomass from a pressurized hydrothermal reactor comprising
 (a). A sluice chamber loading device 
 (b). A sluice chamber 
 (c). A sluice chamber inlet valve adapted to seal an opening to reactor pressure when closed 
 (d). A sluice chamber outlet valve adapted to seal an opening to atmospheric or outlet pressure when closed and adapted for non-explosive release of pretreated biomass 
 (e). A sluice chamber unloading device, and 
 (f). A biomass outlet adapted for non-explosive release of pretreated biomass, and 
 (g). Separate ventilation valve systems that ventilate steam from reactor pressures down to intermediate levels of pressures and from intermediate levels of pressure down to outlet pressures; wherein said sluice chamber is L-shaped. 
 
     
     
       2. The apparatus of  claim 1  wherein the separate ventilation valve systems ventilate in two pressure stages. 
     
     
       3. The apparatus of  claim 2  wherein one stage ventilates from 15 bar to 3 and one stage ventilates from 3 bar to atmospheric pressure. 
     
     
       4. The apparatus of  claim 1  wherein the separate ventilation valve systems ventilate in three or more stages. 
     
     
       5. The apparatus of  claim 1  further comprising an outlet chamber that is adapted to provide variable temperature and pressure conditions. 
     
     
       6. The apparatus of  claim 5  wherein the outlet chamber is adapted to provide temperature of at least 140° C. 
     
     
       7. A method for removing pretreated biomass from pressurized hydrothermal reactors comprising
 (a). Providing a reactor unloading device comprising a sluice chamber that is fitted with ventilation valves that can be regulated so as to release reactor steam and thereby depressurize said sluice chamber in a process that is comparatively gradual relative to steam explosion and that further comprises a sluice chamber loading device and a sluice chamber unloading device, 
 (b). Using said reactor unloading device to load pretreated biomass from a pressurized reactor into the sluice chamber through an open inlet valve that is adapted to seal an opening to reactor pressure when closed, while the outlet valve that is adapted to seal an opening to atmospheric or outlet pressure when closed, 
 (c). Closing the inlet valve, 
 (d). Depressurizing the sluice chamber to atmospheric or outlet pressure, 
 (e). Opening the outlet valve, 
 (f). Unloading the pretreated biomass at atmospheric or outlet pressure, 
 (g). Closing the outlet valve, and 
 (h). Repressurizing the sluice chamber prior to opening the inlet valve for an additional removal cycle. 
 
     
     
       8. The method of  claim 7  wherein furfural content of the insoluble fiber fraction of unloaded biomass is less than about 50% of the furfural content within the reactor. 
     
     
       9. The method of  claim 7  wherein depressurization is accomplished by means of separate ventilation valve systems that ventilate steam from reactor pressures down to intermediate levels of pressures and from intermediate levels of pressure down to outlet pressures. 
     
     
       10. The method of  claim 9  wherein the separate ventilation valve systems comprise two stages. 
     
     
       11. The method of  claim 9  wherein the separate ventilation valve systems comprise three or more stages. 
     
     
       12. The method of  claim 7  wherein steam ventilated during depressurization is recycled to use in further production processes such as drying systems, evaporation systems, or biomass preheating. 
     
     
       13. The method of  claim 7  further comprising subjecting biomass to further adjustments of temperature and pressure in an outlet chamber. 
     
     
       14. The method of  claim 13  wherein the pressure in the outlet chamber is adjusted within the range 50 to 200 torr. 
     
     
       15. The method of  claim 13  wherein the pressure in the outlet chamber is adjusted within the range 200 to 700 torr. 
     
     
       16. The method of  claim 13  wherein the temperature in the outlet chamber is adjusted to at least 13° C.